It is known from U.S. Pat. No. 5,524,146 to access information services delivered in formats such as voice, data, facsimile or video, by dialling short dedicated access codes. This removes the need for a user to recall a large number of telephone numbers. A user may be prompted with menu options, selectable by entering more digits, to identify a particular service provider or a particular service. This enables access from POTS (Plain Old Telephone System) handsets, capable of sending DTMF tones, with no additional interface capability. However, no provision is made for accessing services which require more complete interaction with the user, e.g. input of a message to be faxed or e-mailed to a third party, or address of a host on the internet.
One way of making it easier to access such information services is known from U.S. Pat. No. 5,524,139. The manual access by entry of appropriate DTMF tones, and waiting for prompts, is recorded. This enables automated access by automatic generation of the tones with appropriate delays, upon request by the user.
For access to services requiring more complex interaction, it is known to provide a server which recognizes Tagged Text Mark Up Language (TTML) commands sent by a user.
TTML is known from Smart Messaging Specification Revision 0.9.9, Jun. 6, 1997 Draft, Nokia MobilePhones Ltd. to enable access to a range of services such as e-mail or fax delivery of messages, or internet browsing, by providing a server which interprets commands sent from a telephone handset. It provides means to:
enter text into fields; PA1 make selections from different kinds of menus; and PA1 jump to links (using anchors). PA1 space=2 key presses PA1 -=3 key presses PA1 &gt;=7 key presses PA1 &lt;=6 key presses PA1 .=4 key presses PA1 :=6 key presses PA1 CR=1 key presses PA1 @=4 key presses
However, the telephone needs a tailored interface to facilitate generation of appropriate strings of characters. Although the strings can be generated manually, without such an interface, from many standard handsets, the strings of characters are difficult to remember and many of the characters are not visible on the keypad and require multiple button presses. On many phones the special characters used in TTML (such as &lt;&gt;:.) may need an extended keypad or may not be available at all. For a Nortel PCS 1911 phone:
This makes the services difficult to access for users and limits the use of the service by non-TTML enabled phones. It means that it is more difficult to add new services, since users have difficulty recalling how to use a limited number of services. Also, the commands take up a considerable proportion of the limited length (160 characters) of a single SMS message (a GSM bearer service), thus limiting the length of transactions users may deliver to servers.
It is also known to access a particular device from a telephone, using a relatively simple set of commands, e.g. to control an answering machine remotely. A conventional 12 key telephone keypad is used, typically using the "#" key to delimit by indicating the end of numeric entries.
Appropriate entries are prompted by an Interactive Voice Response (IVR) unit. However such strings of characters used as commands have a single purpose, and do not form a language, to be interpreted and used in various combinations to create many different commands. Also there is no provision for accessing different types of service, only different commands or parameters for a single type of service, or controlling a single system.